In recent years, a transmission line such as a cable or an air hose has been widely used to supply energy or transmit a signal in various industrial machines such as semiconductor equipment, a clean room facility, and a robot. Further, a transmission line veyor has been used to move the transmission line while safely protecting the transmission line. The transmission line veyor is also called a cable veyor.
In general, the transmission line veyor includes a plurality of unit blocks that is arranged in a line and a connection part for connecting the plurality of unit blocks. The connection part connects the plurality of unit blocks so as to allow the transmission line veyor to be bent.
However, in the transmission line veyor described above, friction between the unit blocks that are disposed adjacent to each other and friction between the unit blocks and the transmission line may be caused while the transmission line veyor is repeatedly bent and stretched. Accordingly, in the transmission line veyor, noise and dust may be generated while the transmission line veyor is repeatedly bent and stretched. The noise aggravates working conditions and the dust causes malfunction in the industrial machine. For this reason, a countermeasure against such problems needs to be established.
As the countermeasure, a flexible sleeve has a structure shown in FIGS. 1 and 2. FIG. 1 is a side view of a sleeve for a transmission line, and FIG. 2 is a cross-sectional view taken along A-A′ of FIG. 1.
A sleeve 10 for transmission line includes one end 12 that is fixed to a fixation part of an industrial machine and the other end 14 that is fixed to a movement part of the industrial machine to reciprocate together with the movement part. Further, the sleeve 10 includes a flexible upper member 20 and a flexible lower member 40. Parts of the upper member 20 and parts of the lower member 40 are attached to each other as illustrated in FIG. 2, and transmission lines 16 are inserted into accommodation spaces 50 between other parts of the upper member 20 and other parts of the lower member 40 that are not attached to each other.
Since the sleeve 10 does not have joints, dust and noise are hardly generated even when the sleeve is repeatedly bent and stretched. However, when the sleeve 10 is long and the transmission lines 16 are heavy, the sleeve 10 is slack by the self-weight of the transmission lines 16 as shown in FIG. 1. Accordingly, a support module for preventing the slack is inserted into two accommodation spaces that are disposed at the outermost positions. Hereinafter, a support module according to the related art will be described with reference to FIGS. 3 and 4. FIG. 3 is a side view of a support module of a sleeve for a transmission line according to the related art, and FIG. 4 is a cross-sectional view taken along B-B′ of FIG. 3.
As show in FIGS. 3 and 4, a sleeve support module 60 according to the related art includes a flexible flat plate 62 and a plurality of slack-preventing blocks 64 that is fixed to the flat plate 62 so as to be arranged in a longitudinal direction of the flat plate 62. The flat plate 62 extends to penetrate through lower ends of the slack-preventing blocks 64, so that the slack-preventing blocks 64 are fixed to the flat plate 62.
When the flat plate 62 is bent, the neighboring slack-preventing blocks 64 are spaced apart from each other. However, when the flat plate 62 is stretched, the neighboring slack-preventing blocks 64 come in contact with each other. Accordingly, when the support module 60 is inserted into the accommodation spaces 50 of the sleeve 10 for a transmission line, it is possible to prevent the sleeve 10 from being slack.
However, in the support module 60, the radius of curvature R of the bent flat plate 62 is not restricted. Accordingly, when a force is applied to the support module 60 while being bent as illustrated in FIG. 3, there is a problem in that a bent portion 62a of the flat plate 62 is broken.
Further, in the support module 60, the flat plate 62 extends to penetrate through the lower ends of the slack-preventing blocks 64, so that the slack-preventing blocks 64 are fixed to the flat plate 62. For this reason, there is a problem in that it is difficult to replace only a part of the plurality of slack-preventing blocks 64.
Furthermore, when the support module is inserted into the sleeve 10 and then is not fixed thereto, the support module 60 may be separated from the accommodation spaces 50 during the reciprocating of the other end 14 of the sleeve. Accordingly, a means for fixing the support module 60 to the sleeve 10 is needed.
Moreover, in the support module 60, weights of portions positioned between the bent portion 62a of the flat plate 62 and the other end 14 are offset only by a weak elastic restoring force of the bent flat plate 62. Accordingly, in the support module 60, the radius of curvature R of the sleeve 10 is hardly restricted.
Moreover, in the support module 60, the sleeve 10 is prevented from being slack by allowing the slack-preventing blocks 64 to come in contact with each other, but the slack is prevented only when the sleeve 10 is relatively short. Accordingly, when the sleeve 10 is long, the sleeve 10 is slack even when the support module 60 is used.